1. Field of the Invention
The present invention relates to a drying unit for washing machines that is capable of drying the laundry using hot wind, and, more particularly, to a drying unit for washing machines that is capable of condensing damp air in a tub in an air and water cooling fashion and heating the condensed air by means of a heater to generate hot wind.
2. Description of the Related Art
FIGS. 1 and 2 are views showing a drum washing machine with drying function.
As shown in FIGS. 1 and 2, the washing machine comprises: a cabinet 2 having a door attached to the front part thereof; a tub 4 disposed in the cabinet 2 while being supported by a damper 3; a drum 6 rotatably disposed in the tub 4, the drum 6 having a plurality of water holes 5 formed at the circumferential surface thereof; and a driving unit 10 disposed at the outside of the tub 4, the driving unit 10 being connected to the drum 6 via a rotary shaft for rotating the drum 6.
To the upper part of the tub 4 is connected a water supply pipe 12 for supplying wash water to the tub 4. On the water supply pipe 12 is disposed a water supply valve 14.
The water supply valve 12 is disposed such that the water supply valve passes through a detergent box 16 for containing detergent. If detergent is contained in the detergent box 16, therefore, the detergent in the detergent box 15 is supplied with wash water to the tub 4 when the wash water is supplied through the water supply pipe 12.
To the lower part of the tub 4 is connected a drainage pipe 18 for draining wash water in the tub 4 out of the washing machine. On the drainage pipe 18 is disposed a drainage pump 19.
The drum 6 is provided at the inner wall thereof with lifts 7. Consequently, when the drum 6 is rotated while the laundry is put in the drum 6, the laundry is lifted by the lifts 7, and then falls from the lifts 7 due to gravity.
The washing method of the washing machine with the above-stated construction comprises the steps of: a washing step of removing stain from the laundry; a rinsing step of rinsing the laundry with clean water; and a dewatering step of removing moisture from the laundry, said steps being generally performed in order. Alternatively, the steps may be selectively performed according to user's selection.
The washing machine shown in FIGS. 1 and 2 further comprises a drying unit 20 for forcibly drying the laundry in a short time using hot wind instead of a natural drying process after the laundry is washed.
The conventional drying unit 20 comprises: a condensing duct 22 connected to the lower part of the tub 4; a drying duct 24 connected to the upper part of the tub 4; a blower 26 disposed between the drying duct 24 and the condensing duct 22; a cooling water channel 28 for supplying cooling water into the condensing duct 22; a cooling water valve (not shown) disposed on the cooling water channel 28; and a heater 29 mounted in the drying duct 24.
With the drying unit 20 mounted to the washing machine shown in FIGS. 1 and 2, the washing machine is capable of performing a drying step of forcibly drying the laundry using hot wind.
Specifically, when wet laundry is put in the drum 6, and then the drying step is performed, the blower 26 is operated. As a result, air in the tub 3 passes through the condensing duct 22 and the drying duct 24, and is then supplied again into the tub 4. In this way, the air is circulated. At the same time, cooling water is supplied to the condensing duct 22 through the cooling water channel 28, and the heater 29 is operated.
Consequently, the air in the tub 4, which is damp due to the wet laundry, is blown to the condensing duct 22, where the damp air is condensed by the cooling water. At this time, the cooling water supplied to the condensing duct 22 is introduced into the tub 3, and is then drained out of the washing machine through the drainage pipe 18.
The air condensed in the condensing duct 22 is blown to the drying duct 24, where the condensed air is heated by the heater 29 such that the condensed air is changed into high-temperature and low-humidity hot wind. The hot wind generated in the drying duct 24 is blown to the tub 4 such that the wet laundry put in the drum 6 is dried by the hot wind.
The above-mentioned drying step performed by the drying unit of the washing machine is carried out for several tens of minutes such that the laundry put in the drum 6 is completely dried.
In the conventional drying unit for washing machines, however, the cooling water is continuously supplied to the condensing duct while the drying step is carried out for several tens of minutes, and the cooling water supplied to the condensing duct is drained out of the washing machine through the drainage pipe 18. Consequently, the conventional drying unit for washing machines has a problem in that water consumption is excessive.